Unison dimmers that dim despite being config'd not to

Ron

 As we so love, I have some questions about your question.  How long has this been going on?  Based on you version of Unison this seems likely to be an installation with a few years under it.  What are the loads that are being affected - incandescant, fluorescent or other?  What kind of dimmer rack are the loads coming from?  Is it a Sensor rack (Red beacon or Blue beacon), a Unison rack, or other?  If it is an ETC rack, what kind of module are the loads connected to?  If by happy chance they are connected to relays, this couls be a lmp or ballast issue.  Also, if the loads are on an ETC rack, there is a way to view the levels that the load is being controlled at.  Fianlly do you have a copy of your light designer config tucked away?  If not it is retrievable form the processor which will either be in a DR dimmer rack or an ER control enclosure.

 Finally, feel free to call ETC Tech Support at 800-775-4382 to work with a tech.  In light of full disclosure, I am not currently a tech but used to play one on stage(s).

 Thanks,

Ahh yes, more questions.  No matter how hard I try, y'all think of something else to ask.

Yes, the system has been in use for several years.  Six, actually. Yes, it's been doing it since installation. The lamps in the fixtures are compact floros. The dimmers are in a Unison DR rack.  They are not connected by relays.  Due to the way the system was laid out, they share a dimmer module with a dimmed house light circuit.  Since ETC doesn't make split modules (not that I'm aware), these are also on a dimmer.  Strangely, even though this is dimming CF lamps, there doesn't seem to be a noticeable decrease in lamp life.  Granted they might be dimmable CFs, but I rather doubt it.  I don't believe this is a lamp or ballast issue since there are about a half dozen independant fixtures that are affected simultaneously.

 I do have a copy of the config squirrelled away somewhere.  I have had the config rewritten by ETC Tech Support once before, but it was for an entirely different issue.

 This is a low priority for us, but it is climbing the list.  Our EH&S department is starting to justify its existance, so this might become really important.  Regardless, being able to fix this problem would just make our place a bit nicer.  I'm *thiiiis* close to doing a bit of corrective rewiring, but I really don't want to.

....Ron

First thought to come to mind was - Why are stair lights connected to a dimming system ?.

I would think that the stairs are a path of egress in an emergency ?, and as such, the fluorescents would want to be always ON ?, as well as connected to an emergency power source - local battery/generator system ?.  

Can I assume the stairs are visible to audience members during a show and that leaving the lights on is intrusive to a performance ?.  FWIW, we deal with this with doors that have panic bars as well as curtains across the entry way.

 I would certainly suck the configuration file out of Unison and send ot off the ETC for a look at.  Easy to do as the processor has a 3.5 floppy drive on the side.

Steve Bailey

Brooklyn College

Ron

 This helps a lot.  The next thing I would recommend is to set the dimmers to a firing mode of Non-Dim at the dimmer rack.  Even though the loads are on a dimmer module, the individual dimmer can be set to this mode individually.  I, sadly, have forgotten how to do this on a DR Rack.  If you call Technical Services, they should be able to talk you through it.  I would hate to steer you wrong on the steps and cause furter issues.  If the fixture still does the dimming thing after that, then I would start looking at wire.

Good luck,

The lights are in stair halls on either side of the audience, but outside the room (doors and walls between the stairs and the house seats).  These are not the step lights in the seating area.  Truthfully they have no reason to be part of the Unison system at all but they are.

This is not an emergency egress problem.  There are 4 doors that lead into the seating area, each with a direct outside exit across the stair hall from the seating area.  The stairs need not be used in the event of an emergency, in fact they have automatic doors to close off the stairs if the fire alarm goes off.  These stairs serve two purposes.  They lead from FOH to back stage, and allow a second path for patrons seated in the forward rows to get to and from their seats.  The entire Unison system has emergency power backup. This may be why the stair hall lights are tied into the Unison, but again, they don't need to be.  We have other lights in the building on emergency backup power that aren't connected to the Unison system.

It's also worth mentioning that the lower lighting level does technically meet code requirements.  I have metered the light at the stair treads.  The problem is that the code is still quite dim, especially when entering the theatre on a sunny day.  This is also why we've let this problem go on for so long.

....Ron

As I understand it, the dimmers in question are configured to be on all the time.  I don't know if this means they are set as non-dims or just kept at full via the brain.  If software can't fix the problem, I have a plan that involves replacing an Air Flow Module with a Constant.  I just don't think there is enough wire in the rack to move from one contact to another further down the rack.

I would be *very* surprised if this was a wiring problem.  The contractor who did the install was very accurate (of the some 3000 connections needed for our lighting system, 3 were found to be incorrect at system turn on) and the wire pulled was specified at one step above code (10ga where 12ga would do, etc).  I'm not saying that its not possible, however.

I guess I'll just have to break down and call Tech Support about it.  I just have to be careful about when I make changes.  The Unison controls all the houselights and the overstage works as well.  I don't want to accidently plunge someone into inky darkness.

....Ron

I'd be looking at the Unison config file to see what might be causing a random dimming of the circuits for the halls.

There's a lot you can screw up in Light Manager, but you can also get it back, just like any console, as the backup file on the floppy generally gets you re-configured after a problem.  Trouble is getting tech support at ETC to figure out the dimmers in question when they look at it in Light Manager.  They almost need to install your config in the shop ER4, hook up the DMX output to working lamp(s) and see what happens.

Are there any timed events, BTW ? - I.E. something that the Unison system does overnight ?.  You state this has been doing this since install, which makes me think it's a funky and un-planned-for operation happening in the configuration.  Also, have you tried a Re-Set ?. 

 Steve B.

Hi, am having the same problem with our system. Were you able to come to a resolution with yours? I am going to try to power cycle and clean it. I don't think it has ever been power down, outside of power outages in the area.